DuraGo BR31157 Rear Vented Disc Brake Rotor Non-Directional swirl finish eliminating the need for machining prior to installation Precise hub hole chamfer ensures a hub centric fit Castings engineered to high metallurical standards for consistant quality, strength and performance Multiple vane configuations force out hot air and pull in cool air for suitable heat dissipation and improved performance Manufactured by ISO certified factories to meet requirements of fit, form and function